perf: query CI metadata only for pull request head

lib/pr_data.js

@@ -60,11 +60,30 @@ export default class PRData {
       this.getThreadData(),
       this.getCommits()
     ]).then(() => {
+      this.mergeHeadCommitChecks();
       this.cli.stopSpinner(`Done loading data for ${prStr}`);
     });
     this.analyzeReviewers();
   }
 
+  mergeHeadCommitChecks() {
+    const headCommit = this.pr.headCommit?.nodes?.[0]?.commit;
+    delete this.pr.headCommit;
+
+    const lastCommit = this.commits.at(-1)?.commit;
+    if (headCommit === undefined && lastCommit === undefined) {
+      return;
+    }
+
+    if (headCommit?.oid !== lastCommit?.oid) {
+      throw new Error(
+        'Unable to match pull request head commit while loading data');
+    }
+
+    lastCommit.checkSuites = headCommit.checkSuites;
+    lastCommit.status = headCommit.status;
+  }
+
   analyzeReviewers() {
     this.reviewers = new ReviewAnalyzer(this).getReviewers();
   }

lib/queries/PR.gql

@@ -23,6 +23,35 @@ query PR($prid: Int!, $owner: String!, $repo: String!) {
           path
         }
       },
+      # CI data is only consumed for the pull request's head commit. Querying
+      # it for every commit multiplies the GraphQL rate-limit cost.
+      headCommit: commits(last: 1) {
+        nodes {
+          commit {
+            oid
+            checkSuites(first: 100) {
+              nodes {
+                app {
+                  slug
+                }
+                conclusion,
+                status,
+                checkRuns(first: 40) {
+                  nodes {
+                    name
+                    status
+                    conclusion
+                    detailsUrl
+                  }
+                }
+              }
+            }
+            status {
+              state
+            }
+          }
+        }
+      },
       title,
       baseRefName,
       headRefName,

lib/queries/PRCommits.gql

@@ -25,26 +25,6 @@ query Commits($prid: Int!, $owner: String!, $repo: String!, $after: String) {
             message
             messageHeadline
             authoredByCommitter
-            checkSuites(first: 100) {
-              nodes {
-                app {
-                  slug
-                }
-                conclusion,
-                status,
-                checkRuns(first: 40) {
-                  nodes {
-                    name
-                    status
-                    conclusion
-                    detailsUrl
-                  }
-                }
-              }
-            }
-            status {
-              state
-            }
           }
         }
       }

test/unit/graphql_queries.test.js

@@ -0,0 +1,26 @@
+import { readFileSync } from 'node:fs';
+import { describe, it } from 'node:test';
+import assert from 'node:assert';
+
+const prQuery = readFileSync(
+  new URL('../../lib/queries/PR.gql', import.meta.url), 'utf8');
+const commitsQuery = readFileSync(
+  new URL('../../lib/queries/PRCommits.gql', import.meta.url), 'utf8');
+
+describe('GraphQL queries', () => {
+  it('requests CI details only for the pull request head commit', () => {
+    const headCommitStart = prQuery.indexOf(
+      'headCommit: commits(last: 1)');
+    const headCommitEnd = prQuery.indexOf('\n      title,', headCommitStart);
+    const headCommitQuery = prQuery.slice(headCommitStart, headCommitEnd);
+
+    assert.notStrictEqual(headCommitStart, -1);
+    assert.notStrictEqual(headCommitEnd, -1);
+    assert.match(headCommitQuery, /checkSuites\(first: 100\)/);
+    assert.match(headCommitQuery, /checkRuns\(first: 40\)/);
+    assert.match(headCommitQuery, /status \{\s+state\s+\}/);
+    assert.doesNotMatch(commitsQuery, /checkSuites/);
+    assert.doesNotMatch(commitsQuery, /checkRuns/);
+    assert.doesNotMatch(commitsQuery, /\sstatus\s*\{/);
+  });
+});

test/unit/pr_data.test.js

@@ -23,6 +23,24 @@ function toRaw(obj) {
 const rawPR = toRaw({
   repository: { pullRequest: firstTimerPR }
 });
+const headCommitChecks = {
+  oid: oddCommits.at(-1).commit.oid,
+  checkSuites: {
+    nodes: [{
+      app: { slug: 'github-actions' },
+      status: 'COMPLETED',
+      conclusion: 'SUCCESS',
+      checkRuns: { nodes: [] }
+    }]
+  },
+  status: { state: 'SUCCESS' }
+};
+rawPR.repository.pullRequest.headCommit = {
+  nodes: [{ commit: toRaw(headCommitChecks) }]
+};
+
+const commitsWithHeadChecks = toRaw(oddCommits);
+Object.assign(commitsWithHeadChecks.at(-1).commit, headCommitChecks);
 
 describe('PRData', function() {
   const request = {
@@ -34,7 +52,8 @@ describe('PRData', function() {
     .withArgs('https://raw.githubusercontent.com/nodejs/node/HEAD/README.md')
     .returns(Promise.resolve(readme));
   request.text.returns(new Error('unknown query'));
-  request.gql.withArgs('PR').returns(Promise.resolve(rawPR));
+  request.gql.withArgs('PR').callsFake(
+    () => Promise.resolve(toRaw(rawPR)));
   request.gql.withArgs('Reviews').returns(
     Promise.resolve(toRaw(approvingReviews)));
   request.gql.withArgs('PRComments').returns(
@@ -53,7 +72,45 @@ describe('PRData', function() {
     assert.deepStrictEqual(data.pr, firstTimerPR, 'pr');
     assert.deepStrictEqual(data.reviews, approvingReviews, 'reviews');
     assert.deepStrictEqual(data.comments, commentsWithLGTM, 'comments');
-    assert.deepStrictEqual(data.commits, oddCommits, 'commits');
+    assert.deepStrictEqual(
+      data.commits, commitsWithHeadChecks, 'commits');
     assert.deepStrictEqual(data.reviewers, allGreenReviewers, 'reviewers');
   });
+
+  describe('mergeHeadCommitChecks', () => {
+    it('allows an empty commit list', () => {
+      const data = new PRData(argv, new TestCLI(), request);
+      data.pr = { headCommit: { nodes: [] } };
+      data.commits = [];
+
+      data.mergeHeadCommitChecks();
+
+      assert.deepStrictEqual(data.pr, {});
+      assert.deepStrictEqual(data.commits, []);
+    });
+
+    it('rejects missing head commit data', () => {
+      const data = new PRData(argv, new TestCLI(), request);
+      data.pr = {};
+      data.commits = toRaw(oddCommits);
+
+      assert.throws(
+        () => data.mergeHeadCommitChecks(),
+        /Unable to match pull request head commit/);
+    });
+
+    it('rejects a mismatched head commit', () => {
+      const data = new PRData(argv, new TestCLI(), request);
+      data.pr = {
+        headCommit: {
+          nodes: [{ commit: { ...headCommitChecks, oid: 'different' } }]
+        }
+      };
+      data.commits = toRaw(oddCommits);
+
+      assert.throws(
+        () => data.mergeHeadCommitChecks(),
+        /Unable to match pull request head commit/);
+    });
+  });
 });